import React, {
    useRef,
    useEffect,
    useCallback,
    forwardRef,
    useImperativeHandle,
} from "react";
import { StyleSheet } from "react-native";
import { WebView } from "react-native-webview";

const TOMTOM_API_KEY = "MERY8I7LMeYVSLKO5WuV73W9rKJpBLoB";

export interface TomTomMarker {
    id: string;
    latitude: number;
    longitude: number;
    color: string;
    label?: string;
    description?: string;
    isSelected?: boolean;
}

export interface TomTomRoute {
    coordinates: { latitude: number; longitude: number }[];
    color?: string;
}

export interface TomTomDestination {
    latitude: number;
    longitude: number;
    color?: string;
}

export interface TomTomMapRef {
    fitAllMarkers: () => void;
    fitToCoordinates: (
        coords: { latitude: number; longitude: number }[],
    ) => void;
}

interface TomTomMapProps {
    style?: any;
    markers?: TomTomMarker[];
    route?: TomTomRoute | null;
    destination?: TomTomDestination | null;
    initialCenter?: { latitude: number; longitude: number };
    initialZoom?: number;
    onMarkerPress?: (markerId: string) => void;
}

const TomTomMap = forwardRef<TomTomMapRef, TomTomMapProps>(
    (
        {
            style,
            markers = [],
            route,
            destination,
            initialCenter,
            initialZoom = 12,
            onMarkerPress,
        },
        ref,
    ) => {
        const webViewRef = useRef<WebView>(null);
        const isReady = useRef(false);
        const pendingMessages = useRef<string[]>([]);

        const sendMessage = useCallback((msg: object) => {
            const json = JSON.stringify(msg);
            if (isReady.current) {
                webViewRef.current?.injectJavaScript(
                    `handleMessage(${json}); true;`,
                );
            } else {
                pendingMessages.current.push(json);
            }
        }, []);

        useImperativeHandle(
            ref,
            () => ({
                fitAllMarkers: () => sendMessage({ type: "fitAll" }),
                fitToCoordinates: (coords) =>
                    sendMessage({ type: "fitCoords", coords }),
            }),
            [sendMessage],
        );

        useEffect(() => {
            sendMessage({ type: "updateMarkers", markers });
        }, [markers, sendMessage]);

        useEffect(() => {
            sendMessage({
                type: "updateRoute",
                route: route || null,
                destination: destination || null,
            });
        }, [route, destination, sendMessage]);

        const onMessage = useCallback(
            (event: any) => {
                try {
                    const data = JSON.parse(event.nativeEvent.data);
                    if (data.type === "ready") {
                        isReady.current = true;
                        // flush pending
                        for (const msg of pendingMessages.current) {
                            webViewRef.current?.injectJavaScript(
                                `handleMessage(${msg}); true;`,
                            );
                        }
                        pendingMessages.current = [];
                        // Auto fit markers after ready + flush
                        setTimeout(() => {
                            sendMessage({ type: "fitAll" });
                        }, 500);
                    } else if (data.type === "markerPress" && onMarkerPress) {
                        onMarkerPress(data.id);
                    }
                } catch {
                    /* ignore */
                }
            },
            [onMarkerPress],
        );

        const center =
            initialCenter ||
            (markers.length > 0
                ? {
                      latitude: markers[0].latitude,
                      longitude: markers[0].longitude,
                  }
                : { latitude: 48.8566, longitude: 2.3522 });

        const html = buildHtml(center, initialZoom);

        return (
            <WebView
                ref={webViewRef}
                style={[styles.map, style]}
                source={{ html }}
                onMessage={onMessage}
                javaScriptEnabled
                domStorageEnabled
                scrollEnabled={false}
                bounces={false}
                originWhitelist={["*"]}
            />
        );
    },
);

function buildHtml(
    center: { latitude: number; longitude: number },
    zoom: number,
) {
    return `<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
<link rel="stylesheet" href="https://api.tomtom.com/maps-sdk-for-web/cdn/6.x/6.25.0/maps/maps.css">
<script src="https://api.tomtom.com/maps-sdk-for-web/cdn/6.x/6.25.0/maps/maps-web.min.js"></script>
<style>
  * { margin: 0; padding: 0; }
  html, body, #map { width: 100%; height: 100%; }
  .marker-dot {
    width: 28px; height: 28px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    border: 2px solid rgba(255,255,255,0.8);
    font-size: 12px; color: white; cursor: pointer;
    box-shadow: 0 2px 6px rgba(0,0,0,0.4);
  }
  .marker-dot.selected {
    width: 36px; height: 36px;
    border: 3px solid #7c3aed;
    box-shadow: 0 0 12px rgba(124,58,237,0.6);
  }
  .dest-marker {
    width: 24px; height: 24px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    border: 2px solid white;
    font-size: 10px; color: white;
    box-shadow: 0 2px 6px rgba(0,0,0,0.4);
  }
</style>
</head>
<body>
<div id="map"></div>
<script>
var map = tt.map({
  key: '${TOMTOM_API_KEY}',
  container: 'map',
  center: [${center.longitude}, ${center.latitude}],
  zoom: ${zoom},
  stylesVisibility: { trafficFlow: false, trafficIncidents: false }
});

var markers = {};
var routeLayer = null;
var destMarker = null;

function clearMarkers() {
  Object.values(markers).forEach(function(m) { m.remove(); });
  markers = {};
}

function clearRoute() {
  if (routeLayer && map.getSource('route')) {
    map.removeLayer('route-line');
    map.removeSource('route');
    routeLayer = null;
  }
  if (destMarker) { destMarker.remove(); destMarker = null; }
}

function handleMessage(data) {
  if (data.type === 'updateMarkers') {
    clearMarkers();
    (data.markers || []).forEach(function(m) {
      var el = document.createElement('div');
      el.className = 'marker-dot' + (m.isSelected ? ' selected' : '');
      el.style.backgroundColor = m.color || '#7c3aed';
      el.innerHTML = '<svg width="14" height="14" viewBox="0 0 24 24" fill="white"><path d="M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm-2 15l-5-5 1.41-1.41L10 14.17l7.59-7.59L19 8l-9 9z"/></svg>';
      el.addEventListener('click', function() {
        window.ReactNativeWebView.postMessage(JSON.stringify({ type: 'markerPress', id: m.id }));
      });
      var popup = new tt.Popup({ offset: 20, closeButton: false })
        .setHTML('<div style="padding:4px 8px;font-size:12px;"><b>' + (m.label || m.id) + '</b>' + (m.description ? '<br>' + m.description : '') + '</div>');
      var marker = new tt.Marker({ element: el })
        .setLngLat([m.longitude, m.latitude])
        .setPopup(popup)
        .addTo(map);
      markers[m.id] = marker;
    });
  }

  if (data.type === 'updateRoute') {
    clearRoute();
    if (data.destination) {
      var el = document.createElement('div');
      el.className = 'dest-marker';
      el.style.backgroundColor = data.destination.color || '#ef4444';
      el.innerHTML = '<svg width="12" height="12" viewBox="0 0 24 24" fill="white"><path d="M14.4 6L14 4H5v17h2v-7h5.6l.4 2h7V6z"/></svg>';
      destMarker = new tt.Marker({ element: el })
        .setLngLat([data.destination.longitude, data.destination.latitude])
        .addTo(map);
    }
    if (data.route && data.route.coordinates && data.route.coordinates.length > 1) {
      var coords = data.route.coordinates.map(function(c) { return [c.longitude, c.latitude]; });
      map.addSource('route', {
        type: 'geojson',
        data: { type: 'Feature', geometry: { type: 'LineString', coordinates: coords }, properties: {} }
      });
      map.addLayer({
        id: 'route-line',
        type: 'line',
        source: 'route',
        paint: {
          'line-color': data.route.color || '#4285F4',
          'line-width': 4,
          'line-opacity': 0.8
        }
      });
      routeLayer = true;
    }
  }

  if (data.type === 'fitAll') {
    var allM = Object.values(markers);
    if (allM.length > 0) {
      var bounds = new tt.LngLatBounds();
      allM.forEach(function(m) { bounds.extend(m.getLngLat()); });
      map.fitBounds(bounds, { padding: 60, maxZoom: 15 });
    }
  }

  if (data.type === 'fitCoords') {
    if (data.coords && data.coords.length > 0) {
      var bounds = new tt.LngLatBounds();
      data.coords.forEach(function(c) { bounds.extend([c.longitude, c.latitude]); });
      map.fitBounds(bounds, { padding: 80, maxZoom: 15 });
    }
  }
}

map.on('load', function() {
  window.ReactNativeWebView.postMessage(JSON.stringify({ type: 'ready' }));
});
</script>
</body>
</html>`;
}

const styles = StyleSheet.create({
    map: { flex: 1 },
});

export default TomTomMap;